#include <fstream>
#define NMAX 1005

using namespace std;

ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

int n, m, nr;

int A[NMAX][NMAX];
int sol[NMAX];

void citire();
void parcurgere_euler(int);

int main()
{
    citire();
    parcurgere_euler(1);
    for(int i=1; i <= nr; i++)
        fout<<sol[i]<<' ';
    return 0;
}

void citire()
{
    int x, y;
    fin>>n>>m;

    for(int i=1; i <= m; i++)
    {
        fin>>x>>y;
        A[x][y]++;
        A[y][x]++;
    }
}

void parcurgere_euler(int start)
{
    sol[++nr] = start;

    for(int i=1; i <= n; i++)
        if(A[start][i] > 0)
        {
            A[start][i]--;
            A[i][start]--;
            parcurgere_euler(i);
        }
}